This invention relates generally to safety implements for railed vehicles. Specifically, the invention relates to hinged derailing devices which may be selectively deployed onto a rail for engaging and derailing wheels of railed vehicles.
Derails are safety implements that are placed on a rail to prevent or limit unintended movement of a railed vehicle. They are used extensively in the railroad industry as a means for preventing injury to personnel and damage to property. Typical derails are configured to be manually or automatically movable from a retracted position, in which a wedge-like deflecting block is disposed adjacent a rail, to a deployed position, in which the deflecting block is disposed on top of and aligned with the rail to engage and deflect an oncoming wheel.
Hinged derails, which include a deflecting block mounted on a derail shoe adapted to pivot about a pivot axis, usually defined by a hinge pin, relative to a base, are known in the art. Such derail configurations are disclosed, for example, in U.S. Pat. No. 1,627,094 to Hayes. In operation, the derail shoe is pivoted from its retracted position to its deployed position, where it is aligned with the rail. Proper alignment requires not only lateral alignment of the deflecting block with the rail, but also horizontal alignment in which the bottom surface of the deflecting block is substantially horizontal and supported on an upper surface of the rail. Proper alignment of the deflecting block is important for the derailing device to function safely.
There are a number of different rail sizes in existence and use today. These usually range from 5-inches to 7.5-inches. The variance in rail sizes presents a problem for adapting prior art hinged derails to different rail environments. This difficulty arises because the pivot axis of prior art hinged derails is fixed relative to the rail height. Thus, in order to obtain the proper alignment of the deflecting block of prior art hinged derails for a given rail size, the derail must be constructed according to particular dimensions applicable to that particular rail size. Moreover, shimming or other modifications to the rail system are frequently required to obtain proper derail block alignment with prior art hinged derails. Accordingly, a number of different derailing device configurations are required in order to accommodate the variety of rail sizes in existence today. This results in significant manufacturing cost and effort. Thus, there remains a need for a hinged derail that is easily adaptable to a variety of rail sizes.
An additional problem with prior art hinged derails is that actuating systems for are subjected to rather large forces as the rather massive derail block must be lifted using a lever-like arrangement. There is thus an additional need for an actuating system which is capable of repeated and dependable operation under the stresses created by these large forces.